Switch interlock device



Oct. 15, 1929. BURNS 1,732,181

I SWITCH INTERLOCK DEVICE Original Filed Feb. 27. 1 2 3 Sheets-Sheet 1Oct. 15, 1929. J BURNS SWITCH INTERLOCK DEVICE Original Filed Feb. 27, 13 Sheets-Sheet Oct. 15, 1929. J. BURNS SWITCH INTERLOCK DEVICE 3Sheets-Sheet 3 Original Filed Feb. 27, 1920 Patented Oct. 15, 1929UNITED STATES PATENT OFFICE JAMES F. BURNS, OF PHILADELPHIA,PENNSYLVANIA, ASSIGNOB T V. V. FITTINGS COMPANY, OF PHILADELPHIA,PENNSYLVANIA, A CORPORATION OF PENNSYL- VANIA SWITCH INTER-LOCK DEVICEOriginal application filed February 27, 1920, Serial No. 361,852.Divided and this application filed November 5, 1920.

One object of my invention is to provide a novel device for preventingopening of the door of a compartment such as that in which the fusereceptacles or other accessories removable or operative by hand andassociated with an electric switch, may be mounted, until such switch isfully opened, and which will prevent the closure of the switch as longas said door remains open, the door being auto- 19 matically unlocked assoon as the switch is opened and the switch being automatically lockedin its open position as long as the door is in any other position thanfully closed.

I also desire to provide a novel form of 23 switch controlling mechanismin combination with door locking means of the type above indicated,whose parts shall be so arranged that the operation of looking orunlocking of the door shall not interfere with the quick and positiveopening and closing of the switch.

These objects and other advantageous ends I attain as hereinafter setforth, reference being had to the accompanying drawings, in

Fig. 1 is a perspective view of a safety switch constructed inaccordance with my invention, and having its casing in the closedposition;

Fig. 2 is a plan of the switch shown in Fig. 1, with the covers removedto show the detail construction of the controlling mechanism Fig. 3 is avertical section on the line 3-3, Fig. 2;

Figs. 4 and 5 are vertical sections on the line 4-4, Fig. 2,illustrating the switch in its open and closed positions;

Figs. 6 and 7 are elevations illustrating the operation of thecontrolling mechanism for 49 i the door of the fuse compartment; and

Fig. 8 is an elevation, partly in section, taken on the line 88, Fig. 2,showing the detail construction of the operating handle and itsassociated parts.

i In the above drawings 1 represents an elongated containing box orcasing preferably of pressed sheet metal, having in the present instancea fuse compartment 2 and a switch compartment 3 separated by atransverse partition 4;there being a hinged cover 5 for r Ur)" SerialNo. 421,863.

the fuse chamber or compartment 2 and a second hinged cover 6 forclosing the switch compartment 3, which is preferably of greater depththan said former chamber. This latter cover 6 has a slot for a springstrip 7 projecting outwardly from the top of the partition 4 and formedwith projecting shoulders 8 immediately above the level of the topsurface of said cover when this is closed, so as to prevent itsaccidental opening.

The slot for the strip 7 is of such width that these shoulders willclear its edge when said strip is sprung in one direction from itsnormal position, thereby allowing the cover to be raised, and the end ofthe strip is preferably provided with an opening for the reception of apadlock 9 whereby the cover may be locked in its closed position.

A similar spring retaining strip 10 is mounted on the inside surface ofthe lower end of the casing 1 so that it extends through a slot in thecover 5 of the fuse compartment and it likewise is formed with laterallyprojecting shoulders 11 extending over the top surface of said cover tonormally maintain it closed. It may be moved laterally in its slot tocause said shoulders to clear the edge thereof and to permit the coverto be opened, and it also is provided with an opening 12 for thereception of a suitable lock.

In accordance with my invention, an electric switch is mounted withinthe compartment 3 and a suitable fuse or fuses within the compartment 2.In the case illustrated this switch includes a base plate 13 fixed tothe bottom or back of the casing 1 and having mounted upon it a pair ofswitch clips 14 to which are respectively pivoted two switch blades 15.These are designed to respectively coact with a second pair of clips 16also mounted on the base 13 and each having a terminal screw orequivalent device 17 for the attachment of the terminals of a currentsupply circuit.

Within the compartment 2 is mounted a second base 18 of insulatingmaterial having fixed to it in the present instance two pairs of springfuse clips 1919 of which one of each pair is connected to the adjacentswitch clip 14 by a conductor in the form of a flat bar 20 extendedthrough a suitable insulating bushing 21 in the transverse partition 4.The other clip 19 of each of said bars is provided with a screw orequivalent device 22 for the attachment of a terminal forming part of acircuit to be supplied with current and it is noted that the fuse clips19 of each pair, as well as their associated switch clips 14 and 1G withthe blade 15, are in a straight line extending longitudinally of thecasing.

For operating the switch and controlling the door 5 of the fusecompartments, I provide ajspindleor shaft 23 journalled in the sides ofthe casing and so positioned as to. extend transversely through theswitch compartment immediately under the-conducting bars 20, there beinga sleeve 24 of insulating material mounted on this shaft to. preventshort circuiting with either of said bars. One end of the shaft 23 isextended beyond the outside surface of the casing and has, keyed onit acollar 25 (Fig. 8) providedwith a pro.-

jecting tooth 26 designed to cooperate with the opposite walls of arecess 27 extending longitudinally in the hub or base ofan operatinghandle 28 loosely mounted on said spindle. The latter is provided withfiat, oppositely extending wings 29 from which a series of pins or teeth30 project toward the adjacent side of the casing 1 so as to mesh withthe teeth of a segment 31 rotatably mountedon a headed stud 32projecting from said casing.

This segment is rigidly connected to or formed integral with anintermediate member in the form of a plate 33having a convex circularlycurved portion 35 designed to cooperate with a projecting arm 34 rigidlyfixed to one side of the cover 5 of the fuse compartment from which itprojects at a point adjaa tent its pivotal or hinge axis. Said arm hasformed in one side a concave circularly curved recess 36 so positionedthat when the cover 5 is closed it is concentric with the stud32 and itsradius is slightly greater than that of the curved portion 35 of theplate 33. As a consequence the latter is free to rotate withoutinterference from said arm 34 as long as this occupies the positionshown in Figs. 6 and 7; ie., with the cover 5 in its. fully closedposition. I

In addition the plate 33 likewise has a circularly curved concaveportion 38 extending from one end of the convex portion 35 and so,

placed that when said plate occupies a definite definite position, i.e.,thatshown in Fig. 6,

it is concentric with the pivotal axis of the cover 5 and will permitpassage of the arm 34 whose portion 39 is also concentric with saidpivotal axis and of slightly less radius than the curve of the portion38.

The teeth of the segment 31 are so engaged with the teeth or pins 30 ofthe handle28 that when the latter occupies one ofits extreme positionsin engagement with a stop 40 mounted on one side of the casing 1, theplate 33 is in such a position as to permit the curved portion 39 of thearm 34 to freely pass into the recess defined by its curve 38, and thecover 5 may therefore be freely opened and closed. Vi hen on the otherhand, the handle 28 occupies its other extreme position (Fig. 7) inengagement with a second stop 41 on the casing 1, the plate 33 is in aposition in which its curved portion 35 lies within the recess definedby the portion 36', thus effectually preventing movement of the arm 35and hence of the cover 5 to which it is rigidly connected. Moreover theplate 33 and arm 34 are so de signed that when the handle 28 is in anyother position except in engagement with the stop 40, some portion ofthe curved portion 35 of said plate 33 extends under or interferes withthe arm 34 so that the cover 5 cannot be moved on its pivot. Likewisewhen the cover occupies any but its fully closed position, its arm 34effectually blocks movement of the plate 33 and hence also of the handle28 with its associated mechanism.

Rigidly fixed to the shaft 23 adjacent opposite sides of the switchcompartment 3 are two projecting quadrants 42 each of which is radiallyslotted at 46 for the reception of a'link 43 pivotally connected to itby a pin or rivet 44 adjacent its point of connection with said shaft.These two links project above their respective quadrants and are rigidlyconnected by a cross bar 45 so that they are necessarily moved in unisonabout the pivotal axis provided by said pins 44 with in the limitsdefined by the ends of the slots 46. r

The blades 15 of the switch are connected to move in unison, by a block49 of insulating material for which purpose each of them has fixed in ita pin 50 which projects into one end of said block so that the latter isfree to rotate independently of said blades about said pins as an axis.An eye bolt 51 engages the central portion of the cross bar 45 andextends therefrom through the middle of the connecting block or bar 49to which it is adjustably held by two nuts 52 and 53.

l/Vith this construction it is obvious that the switch blades with theirconnecting block are free to move with the cross bar 45 and the arms 43independently of the quadrants 42 which as before noted are fixed to theoperating shaft 23, and each of these segmental A arms has pivot-allyconnected to one end of its outer portion a link 55 having alongitudinally extending slot through which projects a pin 56 rigidlyfixed to and extending inwardly from the adjacent side of the cas ing 1.Each link is connected to its quadrant 42 by a pivot 57 and has mountedon it a spring 58 confined between two cups 59 and 60, of which thelatter abuts against a stop in the'form of a cotter pin 61 passingtransversely through said link and the other abuts upon a pair ofwashers 62 mounted on the pin 56.

\Vith this arrangement of parts each of the quadrants 42 and itsassociated link 55 constitutes a toggle, which under the action of thespring 58 tends to remain either in the upwz rdly bowed position shownin Fig. i or in the downwardly bowed position shown in Fig. 5. In theformer case that end of each quadrant distant from the link 55 abutsagainstthe partition 4, while in the second case the opposite end ofsaid quadrant engages the floor or bottom of the switch compartment 3.The various parts are so proportioned and arranged that with theoperating shaft 23 and hence the toggles 42-55 associated therewith, inthe positions shown in Fig. 4, the links 43 necessarily occupy suchpositions that the switch blades 15 are in their open positions andcannot engage the clips 16 or even approach dangerously near them eventhough said links be moved to the extreme limit allowed by the slots 46.On the other hand when the operating shaft 28 occupies the positionshown in Fig. 5, with the toggles et2-55 in the downwardly bowedposition, the switch blades are in engagement with their clips 16.

ith the above described mechanism if it be assumed that the switchblades are in en gagement with the clips 16, some part of the curvedportion 35 of the plate 33 lies under or immediately adjacent the curvededge 36 of the arm 34 so that even though the lid or cover 5 of the fusecompartment be released from its spring holding strip 10, it cannot beopened. Under these conditions current is free to flow from conductorsconnected to the terminal screws 17 through the switch and the bars 20to one setof the fuse clips 19 and if fuses are mounted in said clips,to pass through the latter to the terminal screws 22 and hence to thecircuit which is to be supplied with the current. The fuse clips andtheir associated parts withinthe compare ment 2 are therefore alive, andaccess to this compartment is effectually prevented.

In order to open the cover 5 to inspect or replace the fuses in theclips 19, it is necessary to first move the handle 28 in a counterclockwise direction, and it is noted that as it is turned from aposition in engagement with the stop 41 to and into its mid position, itdoes not rotate the operating shaft 28 nor affect the closed switch,although through ,he teeth 30, it turns the blade 33 so as to partiallymove its curved edge from under the arm 3% of the cover 5.

WVhen said handle reaches its mid position, one wall of its recess 27comes into engagement with the tooth 26 of the collar 25 so that saidshaft is thereafter turned with the handle toward the stop 40. As aconsequence, the

, quadrants 42 are swung upwardly, likewise in a counterclockwisedirection, until the II-J ootl of the latter are carried with said armsstantaneously disengaged from their clips 16, as they are swung on theirpivots in counterclockwise direction. This movement of he various partsis finally arrested by the free or outer ends of the quadrants l2striking the partition 4: and it is particularly to be noted that theshoe; due to such stoppage is not transmitted to nor permitted to affectany part of the switching mechanism.

lllereorer not only are the blades capable of moving independently oftheir actuating quadrants 12 but the latter turn are like wise soarranged as to move independently of the actuating handle 28, with theresult that it is a physical impossibility to tease the switch; i.e.,-to partially open or close it or to so slowly open or close it thatan arc would be maintained between its blades 15 and clips 16 On thecontrary the blades are necessarily in their fully closed positionswithin the clips 16 or they are in their fully opened positions C istantfrom the clips without there being any possibility of the operator ofthe handle 28 causing them to remain in any intermediate position.

After such opening of the switch has occurred, the operating handle 28may be brought into el'igagement with its final stop 40, at which timealone the plate 33 is clear of the arm 3%. thus permitting the cover 5to be swung on its hinges to allow of access to the fuse compartment.

If when this cover is open it should be attempted to close the switch,any movement of the operating handle 28 or of the shaft 2?) iseffectually prevented since the plate 38 at once comes into engagementwith the curved portion 39 of the arm 3 which blocks it and it is notuntil the cover is moved to its fully closed position that said armfinally clears said plate, so that closure of the switch when the fusecompartment is open is an impossibility.

lVhen the handle 28 is moved in a cloc wise direction with a view toclosing the switch, as soon as leaves the stop l0, a portion of the edge35 of the plate 38 is inserted under the arm Thereafter said handle maybe freely moved to its mid p tion with the result that said plate isfurther swung under the arm 84 until when the wall of the recess 2?comes into ei'igagement with the tooth of the collar 25 the shaft 23with its quadrants 42 are moved in a clockwise direction. This causes acompression of the springs 58 until the toggles i255 pass the r neutralpoint when the expansion of said springs suddenly causes them to moveinto the position shown in Fig. 5, in which they are brought to rest bytheir engagement with the back of the casing 1. Such sudden movementcauses the members l3 with the blades 15 to likewise be moved from theopen to the fully closed positions altogether independently of thehandle 28 and of said toggles and since the relatively violent movementof the latter is arrested by the casing, there is no resulting shock toor stress upon the switch proper. With the parts in the above notedpositions (Fig. 5) the cover of the fuse compartment is immovably lockedby the members heretofore described which occupy the positions shown inFig. 7.

From the above description it will be noted that the parts are soarranged that when the switch is closed any force exerted upon the doorof the fuse compartment has no effect upon the operating handle tendingto cause this to actuate the switch, and vice verse, when the door isopen, no force exerted upon the handle can have any effect upon saiddoor tending to cause it to close.

Another important feature of my invention resides in the fact that thedoor of the fuse chamber can only be opened when the operating handle isin its fully off position, and is immediately locked from movement byany appreciable displacement of the handle in the direction necessary tocause closure of the switch. Moreover, on the reverse movement of thehandle, there is no possibility of unlocking the door until said handlehas been so far moved as to insure the opening of the switch. Moreoverthe plate 33, which constitutes a member intermediate the operatinghandle and the door, will be found to efiectually prevent a forceexerted on the door 5 to move it from its closed position, being transmitted to the operating handleor in any way affecting the operation ofthe switch mechanism.

While I have referred to fuses and have shown fuse holding clips asmounted within the compartment 2 whose door or cover is made to bedependent upon the switch and its controlling member, it is to beunderstood that the specific device or apparatus in said compartment isimmaterial since the invention broadly contemplates the use of themechanism shown for insuring that current is certainly cut off from theconductor or conductors leading into the compartment before its door orcover can be opened to permit access thereto.

I claim: 7

1. In combination, a casing having a door; an electric switch in thecasing; an operating member for the switch; an arm on the door;

connection with said operating member, so

that movement of the arm and door from their closed positions may beprevented until after the switch has been opened by the operatingmember.

2. The combination of an enclosing casing having a door; an electricswitch in the casing; an operating member for the switch; an arm on thedoor; and an intermediate member held by said arm to prevent closure ofthe switch by the operating member until the door is fully closed, saidintermediate member being so mounted as to prevent force on the doorfrom afiecting said operating member.

3. The combination of an enclosing casing having a door; an electricswitch in the casing; an operating member for the switch; an arm on thedoor; an intermediate member cooperating with said door arm to preventclosure of the switch by the operating memher until the door is fullyclosed; with a lostmotion connection between the operating member andthe switch for insuring locking of the door by the intermediate memberbefore the movable element of the switch is actuated.

4. A casing having a door provided with a cam; mechanism in the casing;a member for actuating said mechanism; turally independent intermediatemember having a cam, said intermediate cam being held by said door camto prevent the operation of said mechanism by said actuating memberuntil said door occupies a predetermined position, said intermediatemember being adapted .to prevent a force exerted on said door fromaffecting said mechanism.

5. The combination of an enclosing casing having a door;mechanism insaid casing; an operating member outside the casing for actuating saidmechanism; an independently supported intermediate member actuated bysaid operating member and including a cam; with a second cam on thedoor, the cam of the intermediate member preventing movement of thesecond 'cam and door when the operating member is in one position andthe door is closed, and the cam on the door preventing movement of theintermediate member and the operating member when said door is open.

6. The combination of an enclosing casing having a door; mechanism inthelcasing; an operating member outside the casing for said mechanism;an intermediate member geared to said operating member; a cam on said intermediate member having a portion concentrlc with its axis of rotationand a second portion concentric with the axis of rotation of the doorwith a cam on said door having a portion concentric with its axis and asecond portion concentric with the axis of the intermediate member, theintermediate member being connected to block movement of the cam on thedoor when the operating member is in any but a predetermined positionand to prevent movement of the operating member when the door is open.

7 The combination of an enclosing casing having a switch and a fusechamber; fuse terminals in the latter chamber; a switch in the formerchamber; a door for the fuse chamber; an operating member for actuatingthe switch; quick make-and-break mechanism in the casing havinglost-motion connections with the switch and with the operating member;and an intermediate member actuated by the operating member for lockingthe door except when the operating member is in its fully off position.

8. The combination of an enclosing casing having a switch and a fusechamber; fuse terminals in the latter chamber; a switch in the formerchamber; a door for the fuse chamber; an operating member for actuatingthe switch; quick make-and-break mechanism in the casing having lostmotion connections with the switch and with the operating member; anintermediate member actuated by the operating member for locking thedoor except when the operating member is in its fully off position; withmeans on the door for preventing movement of the operating member exceptwhen said door is closed.

9. The combination of an enclosing casing having a door; an electricswitch in the casing; an operating member for the switch; with anintermediate member actuated by the operating member to lock the doorshut when the switch is closed and so mounted that the operation of theswitch is not affected by a force exerted on the door tending to openthe same.

10. A casing having a door element; a switch in said casing; anoperating element for said switch; and an intermediate member having ageared connection to one of said elements, whereby the other element maybe locked when said switch is in a predetermined position.

11. A casing having a door element; a switch in said casing; anoperating element for said switch; and an intermediate member having ageared connection to one of said elements so as to prevent a movement ofsaid door element from its closed position until after said switch hasbeen opened by said operating element.

12. A casing having a door element; a switch for said casing; anoperating member for said switch; and an intermediate independentlymounted member actuated by said operating member to lock said door whensaid switch is closed said intermediate member also being held by saiddoor to prevent the closure of the switch until said door is closed.

13. A casing having a door element; a

switch for said casing; an operating member for said switch; anintermediate member actuated by said operating member to lock said doorwhen said switch is closed, said intermediate member also being held bysaid door to prevent the closure of the switch until said door isclosed; and means for mounting said intermediate member, so that theoperation of the switch is not affected by a force on said door tendingto open the same.

14. A casing having a door provided with a cam; mechanism in the casing;an operating member for said mechanism; an intermediate member providedwith a cam and adapted to be actuated by the operating member wherebysaid door may be locked when said mechanism is in a predeterminedposition; and means for so mounting said intermediate member as toprevent a force on the door from affecting the operation of saidmechanism.

15. A casing having a door provided with a cam; mechanism for saidcasing; operat ing means for said mechanism; and a second cam memberhaving a geared connection to said operating means, whereby said doormay be locked when said mechanism is in a predetermined position, saidsecond-mentioned cam being adapted to prevent a force exerted thereon bysaid first-mentioned cam from affecting the operation of said mechanism.

16. A casing having a door provided with a cam; mechanism for thecasing; operating means for said mechanism; and adapted to be actuatedby said operating means and provided with a portion concentric with itsaxis of rotation and a second portion concentric with the axis ofrotation of said door, said door cam having a portion concentric withthe axis of said second mentioned cam and a second portion concentricwith the axis of said door, said second mentioned cam being so mountedas to prevent a force on said door from affecting the operation of saidmechanism.

17. A casing having a fuse chamber; a switch; a door for said fusechamber; an operating member for said switch; quick make-and-breakmechanism having lostmotion connections with said switch and with saidoperating member; and an intermediate structurally independent memberheld by said door to prevent the closing of said switch by saidoperating member until said door occupies a desired position.

18. A casing having switch and fuse members; a switch in said switchchamber; a door for said fuse chamber; an operating member for saidswitch; quick make-andbreak mechanism having lostmotion connections withsaid switch and with said operating member; and an intermediate memberhaving a geared connection to said opl io crating member to prevent amovement of said door from its closed position until said switchoccupies a predetermined position.

19. A casing having a door provided with a cam; a switch in said casing;an operating member for said switch; quick'makeand-break mechanismhaving lost-motion connections with said switch and with said operatingmember; and an intermediate cani having a'geared connection to saidoperating member, whereby said door may be locked for certain positionsof said switch.

20. The combination of an enclosing casinghaving a door; an electricswitch in said casing; an operating member for the switch; means forconnecting said member and switch including a lost-motion connection;door-locking means operated by the mem ber asfit is moved to close theswitch and before motion is transmitted from said member to said switch,said locking means including a member intermediate said operating memberand the door for preventing force applied to said door being transmittedto said operating member, said door being in abutting relation to saidintermediate member when said door is in itsopen position; with quickmake-and-break mecha nism in the casing connected to cause closure ofthe switch independently of the operating member after the latter hasbeen moved to a predetermined position. i

JAMES F. BURNS.

